Building green. The color of a new project? The use of unseasoned lumber to frame a house? Hardly. In the context of building, "green" is a code word for an environmentally sensitive, resource-conserving philosophy of developing real property. In design, the terms "green" and "sustainable" are fundamentally synonymous.

What does it mean to build green?

In simplest terms, it implies using land prudently, responding wisely to climatic conditions and configuring buildings to minimize energy consumption. It also means selecting construction products that perform well, are nontoxic and, when possible, are made from recycled materials.

Many of America's developers and builders express skepticism whenever someone advocates building green. They harbor suspicions that green is just another counterculture cause, a fad promoted by a small band of environmental zealots.

Nonetheless, while green development has yet to become routine, like accommodating the disabled or protecting wetlands, it is becoming less marginalized.

"Green development is good business," said Gerald Hines, chairman of Hines Interests L.P., one of the nation's largest and most successful commercial development companies. "Tenants, owners, purchasers and brokers are all becoming more sophisticated and are realizing the financial and social benefits of green products."

Green development recently was the focus of an all-day workshop at the University of Maryland School of Architecture, where students, like those at other architecture schools, hear about green design and sustainability only occasionally during their studies. The workshop, organized by visiting professor Julie Gabrielli, sensitized students to critical green-design issues and provided them with new information.

The workshop ended with a lecture by William D. Browning of Green Development Services, a consulting group established in 1991 by the Colorado-based Rocky Mountain Institute. Green Development was an adviser for the "greening" of the White House, undertaken in the early 1990s by the Clinton administration, and has worked on projects such as affordable housing developed by Habitat for Humanity, commercial building prototypes developed by the Hines organization and a solar-powered village for the 2000 Olympic Games in Sydney.

As he presented case studies of diverse projects benefiting from energy-efficient, environmentally responsive design, Browning repeatedly hammered home his message. In the world of bottom-line-driven real estate development, the key to persuading people to build green is to demonstrate the economic payoff.

Building green, Browning reminded his audience, entails choosing specific strategies and techniques tailored to each project.

This begins with appropriate land use. Project sites should be intrinsically suitable for development. Unfortunately many sites are undesirable because of adverse geological or soil conditions, steep topography, problematic drainage, valuable tree stands or difficult access to public transportation and utilities.

Green land planning for new communities means paving over less of the landscape, achieved by designing narrower streets and more efficient street networks. Placing buildings closer to streets reduces the lengths of driveways and utility connections, yielding further savings.

The massing, orientation and three-dimensional geometry of a building, whether a house or a museum, determine its architectural quality and character. They also determine the quantity of materials and equipment needed for construction and the amount of labor and energy required to maintain, heat, cool, ventilate and illuminate the building.

Like good siting, efficiently configuring buildings--creating compact volumes while minimizing exterior wall and roof surface areas--conserves materials, labor and energy and reduces heating and cooling loads.

But this approach can pose an aesthetic dilemma. Hyper-efficient design can produce hyper-ugly buildings in the form of featureless boxes. Building green can conflict with building grand.

Thus designers and builders must seek artful compromises reconciling potentially contradictory green and aesthetic agendas. As Brown pointed out during his lecture, there are ways of greening a structure other than mere volumetric compression:

* Roofs and walls can be built of nontoxic, recycled or natural materials with good insulating characteristics.

* Windows and light-reflecting ceilings can be designed to provide a substantial amount of daylight, minimizing dependence on electric lighting. At the same time, unwanted solar heat gain can be reduced by window shading and glass that filters out undesirable radiation.

* Buildings can be configured to induce warm air to rise and vent to the outside, replaced by fresh air taken in through windows at lower levels. This natural "stack" effect contributes to comfort, maintains indoor air quality and reduces the need for continuous air conditioning.

* Within buildings, products made of recycled materials can be specified. This option is more feasible because of increasingly affordable green building components.

Beyond design, recycling construction debris is a greening tactic beginning to enter the consciousness of builders.

Although some of these tactics entail increased capital costs initially, the payoff comes in life-cycle cost savings. In fact, the challenge to building green is not construction cost. Rather it is the cost of the effort still needed to persuade all those who design and build to rigorously pursue green architecture.

Roger Lewis is a practicing architect and a professor of architecture at the University of Maryland.